In response to demands in the market, there have been proposed many technologies which allow a vehicle to urgently travel when a pneumatic tire thereof is punctured during traveling. These many proposals include such a technology disclosed in Japanese Patent Laid-Open Publication No. 10-297226 and Published Japanese Translation of a PCT Application No. 2001-519279 that a support member is fitted onto a rim in the cavity of a pneumatic tire which is assembled to the rim, and supports the tire when punctured to thereby enable run-flat traveling.
The above run-flat support member comprises an annular shell having a support surface located radially outward and two leg portions formed radially inward, and elastic rings attached thereto, and is supported on the rim via the elastic rings. The run-flat support member allows existing wheels and rims to be used without any specific modification, and can therefore be advantageously adopted without causing confusions in the market.
In general, the annular shell of the above-mentioned run-flat member is attached to the elastic rings thereof by bonding to the elastic rings the leg portions of the annular shell which are embedded therein when the elastic rings are formed by heating, and the annular shell and the elastic rings are unitarily structured so that they are not detachable. Therefore, in the case where either the annular shell or the elastic ring is damaged into an unusable state by run-flat traveling at 0 pressure after the tire is punctured, a problem arises such that a new run-flat support member must be purchased even if the other is still usable.
Also, wheels to mount a tire having the same size have different rim shapes, and the same sized tires have different shapes of the inner faces of the tire beads with which the elastic rings come into contact, whereby respective run-flat support members having an annular shell and elastic rings corresponding thereto need to be manufactured. Various types of run-flat support members, therefore, have to be manufactured, and there is a problem of very low manufacturing efficiency.